I have a 2008 Cts the reduced engine power came on won't go over 20 mph had it checked it's not a bad fuel pump not a bad throttle what could it be I'm tired an ?? please help.

engine losing power sign ??? .You mean ENGINE POWER REDUCED ? This has to do with electronic throttle control -Throttle Actuator Control (TAC) System Description

The throttle actuator control (TAC) system is used to improve emissions, fuel economy, and driveability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components:
• The accelerator pedal assembly includes the following components:
- The accelerator pedal
- The accelerator pedal position (APP) sensor 1
- The APP sensor 2
• The throttle body assembly includes the following components:
- The throttle position (TP) sensor 1
- The TP sensor 2
- The throttle actuator motor
- The throttle plate
• The engine control module (ECM)

TAC System Default Actions/Reduce Power Modes
There are 2 reduce power modes that the engine control module (ECM) can default to if an error is detected in the throttle actuator control (TAC) system. If an accelerator pedal position (APP) sensor 1 or APP sensor 2 circuit fault, throttle position (TP) sensor 2 circuit fault, or if a TP sensor 1 circuit fault is detected with some APP angle, the ECM goes into one of the 2 reduce power modes. In this mode, the engine torque is limited so that the vehicle cannot reach speeds of more than 100 km/h (60 mph). The ECM remains in this reduce power mode during the entire ignition cycle even if the fault is corrected.
If there is a condition with the throttle actuator control circuits, throttle actuator command vs actual position fault, return spring check fault, or a TP sensor 1 circuit fault, the ECM goes into the other reduce engine power mode. In this mode, the engine speed is limited to 2,500 RPM and the 3-6 fuel injectors are randomly turned OFF. At this time the Reduced Power indicator is commanded ON. The ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected. Observe, if a TP sensor 1 or throttle actuator control circuit fault is present at the time the vehicle is at idle, with no accelerator pedal angle, the engine may stall.
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You need to have a qualified repair shop check it out.

Sorry , no reset for the fuel pump . Reduced engine power message is for the TAC - throttle actuator control system . Electronic throttle control . Reduced Engine Power: Throttle Actuator Control (TAC) System Description for the 3.6L engine or Throttle Actuator Control (TAC) System Description.TAC System Default Actions/Reduce Power Modes
There are 2 reduce power modes that the engine control module (ECM) can default to if an error is detected in the throttle actuator control (TAC) system. If an accelerator pedal position (APP) sensor 1 or APP sensor 2 circuit fault, throttle position (TP) sensor 2 circuit fault, or if a TP sensor 1 circuit fault is detected with some APP angle, the ECM goes into one of the 2 reduce power modes. In this mode, the engine torque is limited so that the vehicle cannot reach speeds of more than 100 km/h (60 mph). The ECM remains in this reduce power mode during the entire ignition cycle even if the fault is corrected.
If there is a condition with the throttle actuator control circuits, throttle actuator command vs actual position fault, return spring check fault, or a TP sensor 1 circuit fault, the ECM goes into the other reduce engine power mode. In this mode, the engine speed is limited to 2,500 RPM and the 3-6 fuel injectors are randomly turned OFF. At this time the Reduced Power indicator is commanded ON. The ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected. Observe, if a TP sensor 1 or throttle actuator control circuit fault is present at the time the vehicle is at idle, with no accelerator pedal angle, the engine may stall.

What year is the caddy ? power reduced message DTC'S -diagnostic trouble codes are stored in PCM - BCM memory . Your best bet , take it to a qualified repair shop. ENGINE POWER REDUCED
Refer to Throttle Actuator Control (TAC) System Description for the 2.8L engine, Throttle Actuator Control (TAC) System Description for the 3.6L engine or to Throttle Actuator Control (TAC) System Description for the 5.7L engine

If a warning light is on, there's a trouble code stored in the computer. There are well over 800-1,000 possible trouble codes in the average late model vehicle, so asking us to guess what's causing your problem without knowing the code is a complete waste of time. Get the code read. Post it here. THEN we can help

2003 Silverado 2500HD REDUCED ENGINE POWER - Discussion on Topix

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Reduced Engine Power Message Displayed on GM Vehicles

www.underhoodservice.com/tech-tip-reduced-engine-power-message-dis...
Dec 10, 2012 - Tech Tip: Reduced Engine Power Message Displayed on GM Vehicles ... Model year 2008-'10 vehicles must have the engine control module (ECM) reprogrammed ... Do not drop the electronic throttle control components.

Are you getting a ENGINE POWER REDUCED message ? Is the check engine light on ?
Reduced Engine Power Mode
Throttle Actuator Control (TAC) System
electronic throttle control .
When the ECM detects a condition with the TAC system the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Limited torque

?€¢
Limited range of throttle movement

?€¢
Engine OFF

Your going to need to take this to a ASE certified repair shop or the dealer , you probably don't have the diagnostic tools to trouble shoot this problem.
https://youtu.be/oPPLAHSSluw

Engine power reduced , problem with the electronic throttle control ! Watch a couple of video's on youtube , google GM engine power reduced . The gas pedal an the throttle body have position sensor's ,when the PCM/ECM - engine computer see conflicting input's from one of these sensors it send's into a reduced power mode . Your best bet mite be to take it to a qualified repair shop.

It's fuel related, check your fuel filter to see if it's clogged, let me know. Good luck, Jim

I had the same problem with my 2003 denali and came to find out that it was the battery causing the problem. the battery with sufficient power will dictate the tps. if the battery is low or bad, it won't have enough juice to allow the tps to. work. get your battery checked.